Stacking aluminum lowering block?

While driving I was thinking about swapping out the 17" Bullet wheels from my 70 Duster with 8.25 to the 74 and put the 255 cop wheels combo from the 74 to the 70...

The backspacing on the Bullit's would be pretty good for the 65-67 B body rear axle. And the cop wheels would be a better match for the 8.25, although with a 255 they'll be real close to the springs without a small spacer